datetimeField = datetimeField - '30minutes'::timespan in psql 7.0 or above

Actually, it is not so simple.

How can you do this in psql 7.0 or above?
datetimeField = datetimeField - '30minutes'::timespan ( in psql 6.3, 6.5 you can),

while if you use type timestamp, instead of datetime
timestampField = timestampField - '30minutes'::interval
 you will get error msg.:
No such function 'datetime_stamp' with the specified attributes

--
Banghe



Joel Burton wrote:

>
> Is there anything that datetime did that timestamp doesn't?
>
> Could you
>
>    pg_dump | sed | psql
>
> to change the datetimes to timestamp?
>
> --
> Joel Burton   <jburton@scw.org>
> Director of Information Systems, Support Center of Washington